Never drop an enrolled class from upcoming lessons; delete a guardian's children with them; pin the panel's line spacing

Three fixes from testing the branch.

A group class was only listed when its schedule resolved to exact
datetimes, which needs a class time *and* a duration — both optional on
the offering form, and the schedule note exists precisely so a studio can
write "Tuesdays 4:00pm" instead. A class configured that way vanished
from the list, which is the one thing this feature must never do. So
Offering::sessionStarts() splits "when does it meet" from "how long does
it run" (sessionWindows() is that plus the duration, unchanged), and
SessionSchedule degrades instead of disappearing: dated rows with an open
end when there is no duration, and a single row carrying
Offering::scheduleLabel() when there is no time to derive dates from.
Only a class whose last day has passed drops out.

Deleting a guardian now deletes the children linked to them, releasing
each one's lessons and enrolments first. A child account is login-less
and exists only so the guardian has somebody to book for; without the
guardian nobody can reach it, book for it, or be billed for it, so it was
left stranded on the roster still holding slots. A `handled` set makes
the re-entrant delete_user each child deletion fires a no-op, and stops a
circular link recursing.

The upcoming panel never stated its own line-height, so a theme setting
line-height: 0 above it — the usual icon-font reset — was inherited
straight through. Below 1 that produces both reported symptoms at once:
stacked lines overlap, and the status pill's background is shorter than
the text in it. Pinned at the same id-level specificity as the rest.

Tests: composer test (863), composer lint, composer cs all pass.

Co-Authored-By: Claude Opus 5 <[email protected]>

src/Offering/Offering.php

@@ -175,22 +175,19 @@ class Offering {
 	}
 
 	/**
-	 * The concrete start/end datetimes of every session of this group class,
-	 * derived from the class date(s), the class time, and the duration. A weekly
-	 * class yields one window per week from `term_start` through `term_end`; a
-	 * one-off class yields a single window. Returns an empty list unless the
-	 * schedule is fully specified (date, time, and a positive duration), so it can
-	 * never fabricate a session window from partial data.
+	 * The datetime each session of this group class starts, derived from the class
+	 * date(s) and the class time. A weekly class yields one per week from
+	 * `term_start` through `term_end`; a one-off class yields a single one.
 	 *
-	 * @return list<array{start: string, end: string}>
+	 * Deliberately does **not** need a duration: knowing *when* a class meets is a
+	 * separate question from knowing how long it runs, and a studio can quite
+	 * reasonably set the first without the second. Returns an empty list when
+	 * there is no date or no time, since neither can be invented.
+	 *
+	 * @return list<string> `Y-m-d H:i:s` starts, earliest first.
 	 */
-	public function sessionWindows(): array {
-		if (
-			null === $this->termStart
-			|| null === $this->classTime
-			|| null === $this->durationMinutes
-			|| $this->durationMinutes <= 0
-		) {
+	public function sessionStarts(): array {
+		if ( null === $this->termStart || null === $this->classTime ) {
 			return [];
 		}
 
@@ -200,25 +197,85 @@ class Offering {
 		}
 
 		$lastDay = null !== $this->termEnd ? $this->termEnd : $this->termStart;
-		$step    = new \DateInterval( 'PT' . $this->durationMinutes . 'M' );
 
-		$windows   = [];
+		$starts    = [];
 		$cursor    = $first;
 		$cursorDay = $cursor->format( 'Y-m-d' );
 
 		// Cap the walk at ten years of weeks so a term_end before term_start (or a
 		// bad value) can never spin into an unbounded loop.
 		for ( $i = 0; $i < 520 && $cursorDay <= $lastDay; $i++ ) {
-			$windows[] = [
-				'start' => $cursor->format( 'Y-m-d H:i:s' ),
-				'end'   => $cursor->add( $step )->format( 'Y-m-d H:i:s' ),
-			];
+			$starts[] = $cursor->format( 'Y-m-d H:i:s' );
 
 			$cursor    = $cursor->modify( '+7 days' );
 			$cursorDay = $cursor->format( 'Y-m-d' );
 		}
 
-		return $windows;
+		return $starts;
+	}
+
+	/**
+	 * The concrete start/end datetimes of every session of this group class:
+	 * {@see sessionStarts()} closed off with the class duration. Returns an empty
+	 * list unless the schedule is fully specified (date, time, *and* a positive
+	 * duration), so it can never fabricate a session window from partial data —
+	 * callers that block availability or bill per session need both ends.
+	 *
+	 * @return list<array{start: string, end: string}>
+	 */
+	public function sessionWindows(): array {
+		if ( null === $this->durationMinutes || $this->durationMinutes <= 0 ) {
+			return [];
+		}
+
+		$step = new \DateInterval( 'PT' . $this->durationMinutes . 'M' );
+
+		return array_map(
+			static fn( string $start ): array => [
+				'start' => $start,
+				'end'   => ( new \DateTimeImmutable( $start ) )->add( $step )->format( 'Y-m-d H:i:s' ),
+			],
+			$this->sessionStarts()
+		);
+	}
+
+	/**
+	 * The last day this class meets, or null when it has no dates at all.
+	 */
+	public function lastClassDay(): ?string {
+		return $this->termEnd ?? $this->termStart;
+	}
+
+	/**
+	 * Plain-language wording for when this class meets, for the places that have
+	 * to say something about a class whose schedule cannot be resolved to dates.
+	 * Prefers the studio's own note ("Tuesdays 4:00pm") — that field exists
+	 * precisely so a class can describe its schedule without pinning it to a
+	 * time — then the term dates, and finally an honest admission that nothing
+	 * has been set.
+	 */
+	public function scheduleLabel(): string {
+		$note = null !== $this->scheduleNote ? trim( $this->scheduleNote ) : '';
+		if ( '' !== $note ) {
+			return $note;
+		}
+
+		if ( null === $this->termStart ) {
+			return __( 'Schedule to be confirmed', 'unsupervised-schedular' );
+		}
+
+		$start = (string) mysql2date( 'M j, Y', $this->termStart );
+
+		if ( null === $this->termEnd || $this->termEnd === $this->termStart ) {
+			return $start;
+		}
+
+		return sprintf(
+			/* translators: 1: first class date, 2: last class date. */
+			__( '%1$s – %2$s', 'unsupervised-schedular' ),
+			$start,
+			(string) mysql2date( 'M j, Y', $this->termEnd )
+		);
 	}
 
 	public static function fromRow( \stdClass $row ): self {